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<head><meta charset="utf-8"><title>how to explain PhantomData mixing w/ dropck post NLL? #70841 · t-compiler/wg-nll · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/index.html">t-compiler/wg-nll</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html">how to explain PhantomData mixing w/ dropck post NLL? #70841</a></h3>

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<a name="193492974"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193492974" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193492974">(Apr 09 2020 at 18:46)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> <span class="user-mention" data-user-id="116118">@Matthew Jasper</span> <span class="user-mention" data-user-id="119009">@eddyb</span> I reclassified <a href="https://github.com/rust-lang/rust/issues/70841" title="https://github.com/rust-lang/rust/issues/70841">#70841</a> as a documentation issue</p>



<a name="193492996"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193492996" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193492996">(Apr 09 2020 at 18:46)</a>:</h4>
<p>but I will admit I'm at a bit of a loss about how best to describe the semantics</p>



<a name="193493042"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193493042" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193493042">(Apr 09 2020 at 18:47)</a>:</h4>
<p>"PhantomData&lt;T&gt; acts like it holds a T, if it is embedded in a type that has drop glue?"</p>



<a name="193493079"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193493079" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193493079">(Apr 09 2020 at 18:47)</a>:</h4>
<p>I suspect the <em>intent</em> is for it to behave that way when it is in a type with a destructor</p>



<a name="193493096"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193493096" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193493096">(Apr 09 2020 at 18:47)</a>:</h4>
<p>I would avoid "drop glue" in docs but that's just me</p>



<a name="193493146"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193493146" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193493146">(Apr 09 2020 at 18:47)</a>:</h4>
<p>but right now, a neighboring field that holds the destructor will cause dropck to flag the <code>PhantomData</code> too</p>



<a name="193493215"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193493215" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193493215">(Apr 09 2020 at 18:48)</a>:</h4>
<p>so I don't know the best way to describe that. Maybe just "if its embedded in a type that <code>needs_drop</code> " ?</p>



<a name="193496500"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193496500" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193496500">(Apr 09 2020 at 19:14)</a>:</h4>
<p><code>PhantomData&lt;T&gt;</code> affecting dropck is primarily for types with a <code>#[may_dangle] T</code> <code>Drop</code> impl.</p>



<a name="193496644"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193496644" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193496644">(Apr 09 2020 at 19:15)</a>:</h4>
<p>that's true, I had mentioned that somewhere (stackoverflow? a running issue?)</p>



<a name="193570789"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193570789" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193570789">(Apr 10 2020 at 13:52)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> I'm surprised that a neighboring field has an effect</p>



<a name="193571133"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193571133" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193571133">(Apr 10 2020 at 13:56)</a>:</h4>
<p>But I think I would explain it like this:</p>
<ul>
<li>By itself, <code>PhantomData</code> has no semantics, but it used to inform various analyses about what kind of data your type may access using unsafe code or other means.</li>
<li>A <code>PhantomData&lt;T&gt;</code> field affects variance of lifetimes, as it implies that operations on values of this type may wind up accessing values of type <code>T</code>.</li>
<li>The borrow checker sometimes needs to decide what types of values a type may access when dropped. If your type defines a <code>Drop</code> impl, then a <code>PhantomData&lt;T&gt;</code> will be interpreted to mean that your destructor may drop or access values of type <code>T</code>. (If there is no <code>Drop</code> impl, then <code>PhantomData&lt;T&gt;</code> has no effect on the types of values we assume might be accessed.)</li>
</ul>



<a name="193571141"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193571141" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193571141">(Apr 10 2020 at 13:56)</a>:</h4>
<p>But it sounds like that's not quite correct</p>



<a name="193571156"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193571156" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193571156">(Apr 10 2020 at 13:56)</a>:</h4>
<p>I wonder if we <em>should</em> consider this a bug :)</p>



<a name="193571172"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193571172" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193571172">(Apr 10 2020 at 13:57)</a>:</h4>
<p>It's kind of a corner case I guess</p>



<a name="193800628"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193800628" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193800628">(Apr 13 2020 at 18:00)</a>:</h4>
<p>One thing I have been thinking about</p>



<a name="193800652"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193800652" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193800652">(Apr 13 2020 at 18:00)</a>:</h4>
<p>it <em>might</em> actually make sense that the neighboring field has an effect</p>



<a name="193800693"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193800693" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193800693">(Apr 13 2020 at 18:00)</a>:</h4>
<p>(even if it is unclear whether anyone actually planned for this.)</p>



<a name="193800739"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193800739" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193800739">(Apr 13 2020 at 18:01)</a>:</h4>
<p>Specifically: There can be read/write effects to a state behind that neighboring field</p>



<a name="193800914"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193800914" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193800914">(Apr 13 2020 at 18:02)</a>:</h4>
<p>and if the struct designer added the <code>PhantomData</code> due to such read/write effects from the neighboring field's destructor</p>



<a name="193800949"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193800949" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193800949">(Apr 13 2020 at 18:02)</a>:</h4>
<p>(that are not otherwise modeled by <code>dropck</code>, due to use of ... I don't know, <code>*mut</code>/<code>*const</code>) ?</p>



<a name="193800988"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193800988" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193800988">(Apr 13 2020 at 18:03)</a>:</h4>
<p>then this choice seems like it would make sense.</p>



<a name="193801087"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193801087" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193801087">(Apr 13 2020 at 18:04)</a>:</h4>
<p>(I continue to think it would be <em>simpler</em> to document if we were more restrictive here. But given that it would inject breakage without actually adding value, it seems pretty hard to justify...)</p>



<a name="193900411"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/193900411" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#193900411">(Apr 14 2020 at 13:56)</a>:</h4>
<p><span class="user-mention silent" data-user-id="116083">pnkfelix</span> <a href="#narrow/stream/122657-t-compiler.2Fwg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841/near/193496644" title="#narrow/stream/122657-t-compiler.2Fwg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841/near/193496644">said</a>:</p>
<blockquote>
<p>that's true, I had mentioned that somewhere (stackoverflow? a running issue?)</p>
</blockquote>
<p>yes: <a href="https://stackoverflow.com/a/42721125/155423" title="https://stackoverflow.com/a/42721125/155423">Why is it useful to use PhantomData to inform the compiler that a struct owns a generic if I already implement Drop?</a></p>



<a name="194539677"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/194539677" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#194539677">(Apr 18 2020 at 11:28)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> well, we don't know how much breakage, right?</p>



<a name="194539679"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/194539679" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#194539679">(Apr 18 2020 at 11:28)</a>:</h4>
<p>I think there's a case to be made that it's a bug fix, it's definitely a grey line</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/194539680" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#194539680">(Apr 18 2020 at 11:28)</a>:</h4>
<p>Might be worth testing</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/how%20to%20explain%20PhantomData%20mixing%20w/%20dropck%20post%20NLL%3F%20%2370841/near/194539682" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/how.20to.20explain.20PhantomData.20mixing.20w.2F.20dropck.20post.20NLL.3F.20.2370841.html#194539682">(Apr 18 2020 at 11:28)</a>:</h4>
<p>I found your argument persuasive</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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